A high school chemistry teacher and track coach who allegedly sexually assaulted a 16-year-old female student is blaming the medication he takes for Parkinson’s disease.

Police say the incident occurred on June 2 when the teacher, Dale Snyder, and the student were putting away chairs after graduation ceremonies at Milton High School in Milton, Mass.

Snyder, 64, allegedly asked the female student to come back to his vacant classroom. Then, according to the unnamed student, he tried to kiss her several times. He also put his hand on her leg.

Snyder’s attorney, Thomas Lawton, says the medication he is taking for Parkinson’s disease may trigger impulsive conduct and could have increased the chemistry teacher’s libido.

It’s unclear exactly which drug or cocktail of drugs the 27-year Milton High teacher has been taking. However, Parkinson’s drugs are known to cause hypersexuality (as well as compulsive eating and gambling).

Snyder has no prior police record. He’s also a member of the Massachusetts State Track Coaches Association Hall of Fame, notes CBS Boston.